The Globe & Mail – Municipal Infrastructure gets a boost from university expertise
Canadians must be wondering what’s happening to their infrastructure.
From concrete chunks falling off big-city expressways to shopping mall collapses and water main breaks, it all seems to be crum- bling at the same time.
In a way, it is. Much of Canada’s infrastructure was built during the post-Second World War development boom. Since it was estimated to last about 50 years, it has simply passed the best- before date. And this is happening at the same time as a massive migration to urban centres, increasing the need for new in- frastructure and further stressing aging structures.
In 2012, the Federation of Canadian Municipalities released its Infrastructure Report Card, which found that roughly 30 per cent of Canada’s infrastructure was in need of repair or replace- ment. Municipal roads, it re- ported, demanded “urgent attention” and would cost more than $90 billion to replace – more than $7,300 for every Canadian household.
“It’s a perfect storm of factors,” says Nemkumar Banthia, a professor of civil engineering at the University of British Columbia (UBC). “Investment in infra- structure has not kept up, and greater traffic and other loads have increased the demands on these structures compared to when they were constructed.” The resulting “infrastructure gap” – the value of current infra- structure relative to the value of infrastructure that is needed – is growing wider every day.
To help fill the void, leading Canadian researchers are devising new ways to build these structures (and innovative ways to maintain old ones), which could save on replacement costs and add years to the service life. At UBC, Dr. Banthia developed a mixture of high-performance fibres that can be sprayed onto older concrete, increasing its strength and durability. The spray is embedded with fibre optic sensors, which send signals back to engineers and allow them to detect any deterioration in the structures in real time. “It’s analogous to health moni- toring online,” says Dr. Banthia. “Sort of like a pacemaker in a body.”
For city bridges and overpasses, the invention could mean the difference between a timely repair job and a sudden collapse.To effectively maintain our critical infrastructure, says Lamya Amleh, an associate professor of civil engineering at Ryerson University, we have to learn more about how and why it deteriorates. Dr. Amleh and her students conduct large-scale experiments on concrete structures used for bridges and roadways, testing how they behave under varying deterioration conditions.
“Corrosion of reinforcing steel in concrete is a multi-billion- dollar problem,” says Dr. Amleh. “When corrosion attacks the steel, byproducts (iron oxides) accumulate along the steel bar, increasing internal volume and pressure enough to crack the surrounding concrete.”
Dr. Amleh uses a “corroding tank” to test how different materials, such as common road salts, will penetrate concrete and corrode the steel. By better understanding what causes deterioration and how rapidly it occurs, Dr. Amleh is developing new models for predicting a structure’s service life and new criteria for identifying when infrastructure must be replaced.
In the face of failing infra- structure and ongoing municipal funding crunches, innovation may be Canada’s best hope.